Environmental DNA for early detection of invasive species in freshwater ecosystems

Abstract

The expansion of the Invading Species (IS) is a primary threat to global biodiversity and the functioning of freshwater ecosystems, necessitating the development of highly sensitive, timely detection mechanisms. Traditional ecological surveys are time-intensive and costly, and ineffective at detecting species at low abundance or at early stages of invasion. The study critically reviews and proposes a single framework for the application of environmental DNA (eDNA) as a newer, stronger, non-invasive approach to early warning of IS in freshwater systems. We also review the latest state-of-the-art and explain how eDNA assays, in particular, quantitative PCR (qPCR) and metabarcoding, can be used to overcome shortcomings of traditional Surveillance and provide actionable information to the management. A systematic methodology that we propose includes the best sampling processes in multifaceted water bodies to the point of using predictive occupancy models, which enhance the accuracy of the data detected. We determine the practical utility of eDNA in the detection of low-density, hard-to-detect invaders, and thereby substantially shorten the lag time of introduction as compared to detection. Besides, we outline the use of calculation and performance measures in order to transform eDNA not just into a novel research method, but into a normative and working monitoring program. The study affirms the application of eDNA as the most crucial early warning system that would be required to cope with the adverse impacts of biological invasion on sensitive freshwater ecosystems by integrating rigorous field methods with advanced molecular and statistical analysis, all of which would be applied to support quick response intervention and conservation control.